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Home Prevention Breast MRI

Breast MRI

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So I understand that breast MRI is now being used to detect breast cancer and monitor patients with established disease. Which women are recommended to get this test and does it potentially replace older modalities such as mammography and ultrasound?

The American College of Radiology (ACR) has a published a set of guidelines for the performance of contrast-enhanced magnetic resonance imaging (MRI) of the breast published in 2008. MRI of the breast is currently being used to detect and characterize breast disease, assess local extent of disease, evaluate treatment response, and guide biopsy for histologic diagnosis. Findings present on MRI should be correlated with clinical history, physical exam, results of mammography, and other prior breast imaging results. At the present time, breast MRI is not being used to screen the general population of asymptomatic, average-risk women. MRI may miss some cancers that mammography will detect, and thus should not replace mammography as the primary screening modality. Furthermore, MRI should not replace biopsy of a mammographically, cinically, or sonographically suspicious finding. False positives are to be expected with breast MRI. However, rates of biopsy with MRI are similar to that of mammography. In the event that a patient is deemed to be a candidate for breast MRI, the exam should be not be done while patients are in the secretory phase of the menstrual cycle. Increased tissue enhancement that is observed during this time can give rise to increased false positive MRI scans. Thus, the exam should be done in the second week of the menstrual cycle. Furthermore, bilateral breast imaging should be done whenever possible, as many benign conditions such fibrocystic changes are often present in both breasts.

In terms of screening, MRI of the breast is indicated when:

1. Patients have more than a 20% lifetime risk of breast cancer based upon genetic predisposition based upon gene testing or family pedigree, or with a history of mantle radiation for Hodgkin’s disease. These women should still receive standard testing by mammography.

2. Patients have confirmed disease in one breast and require screening of the contralateral breast. MRI has been proven to detect occult malignancy in the contralateral breast in at least 3-5% of breast cancer patients.

3. Patients have received breast augmentation surgery (postoperative reconstruction and free injections). Mammography may be difficult to perform in patients with silicone, saline, and free injection implants with silicone, paraffin, or polyacrylamide gel. The integrity of silicone implants can be assessed by non-contrast MRI.

MRI can also be used to determine the extent of disease in patients with:

1. Invasive carcinoma and ductal carcinoma in situ (DCIS). MRI can help detect mutifocality and multicentricity in such patients. MRI can detect occult disease up to 15-30% of the time in the breast containing the index malignancy. MRI determines the extent of disease more accurately than standard mammography and physical exam. However, it is still not known whether this increased accuracy in evaluating disease alters recurrence rates relative to surgery, radiation, or systemic therapy.

2. Invasion to the deep fascia. MRI evaluation of breast carcinoma before surgery may be useful in both mastectomy and breast conservation patients in order to define the relationship of the tumor to the fascia and its extension into pectoralis major, serratus anterior, and intercostals muscles.

3. Post-lumpectomy with positive margins. Breast MRI can evaluate residual disease in patients whose pathology specimens show close or positive margins for residual disease

4. Neo-adjuvant chemotherapy. Breast MRI may be useful before, during and after chemotherapy to evaluate treatment response and extent of residual disease prior to surgery. A pre-treatment MRI and use of MRI-compatible localization tissue markers are useful in these patients.

Additional indications for breast MRI include:

1. Detecting disease recurrence. Breast MRI is especially useful if there is suspicion for recurrence when clinical, mammographic, and sonographic findings are inconclusive.

2. Evaluating patients with metastatic disease and the primary lesion is unknown and suspected to be of breast origin. Patients with axillary lymphadenopathy and no mammographic or physical findings of breast cancer may benefit from breast MRI as it can sometimes locate the primary tumor and define the disease extent to facilitate treatment planning.

3. Lesion characterization. Other imaging examinations such as ultrasound and mammography may be inconclusive and biopsy could not be performed because of possible distortion on only one mammographic view without a sonographic correlate.

4. Evaluating patients with postoperative tissue reconstruction. Breast MRI can evaluate cancer recurrence in patients with tissue transfer flaps (rectus abdominus, latissimus dorsi, gluteal muscles).

5. Performing MRI-guided biopsy, especially for vacuum assisted biopsy and pre-operative wire localization for lesions that are occult on mammography or ultrasound.


Resources http://www.acr.org/secondarymainmenucategories/quality_safety/guidelines/breast/mri_breast.aspx